Pentek 655005-43 Iron Reduction The Pentair Pentek RFFE10-BB and RFFE20-BB Filter Cartridges are designed to provide an easy and effective method of reducing dissolved iron from water, which greatly improves the taste. This cartridge helps to eliminate the orange and brown stains often found in sinks, toilets, tubs and other plumbing fixtures. It also reduces the possibility of damage to pipes and water heaters and reduces up to 3 ppm of dissolved iron